The invention relates to a pushbutton switch with a ring and a spring-prestressed button. The button terminates flush with the top edge of the ring, so that on at least one side parallel to the longitudinal axis of an actuating finger, the ring is reduced continuously in height more or less to the level of the actuating displacement.
Round pushbutton switches include those of a diameter of between 15 and 25 mm and which have a ring in which a spring-prestressed button is arranged. The spring-prestressed button is arranged such it can be pushed by a predetermined displacement. Buttons which are planar on the top side and which terminate flush with the top edge of the ring are know. In these cases, the ring serves to fasten the switch for reliable and defined operation for securing against actuation as a result of unintentional contact.
During the pushing-down action, however, the fingertip comes into contact with part of the surrounding ring. In particular individuals who have relatively long fingernails find this awkward or uncomfortable, especially since relatively long fingernails usually also come into contact with the opposite section of the ring.
This problem is eliminated by reducing the actuating displacement of the button. However, this requires, on the one hand, a certain precision motor mechanism and, on the other hand, acoustic or optical acknowledgement of the button actuation.
If the height of the ring as a whole were to be lowered, the button would project, with the result that the ring would lose its function as a means for guiding the finger and securing against incorrect operation.